Butterfly valve

Abstract

To provide a butterfly valve that can be used for a long period of time without the need to replace the sealing components. [Solution] The butterfly valve 1 comprises a cylindrical valve body 2, a valve element 3 configured to close a flow path, a valve stem 4 that rotatably supports the valve element 3 relative to the valve body 2, and in a first closed state, at least one first sealing member 5 provided on the upstream side of the flow path and at least one second sealing member 6 provided on the downstream side of the flow path. In the first closed state, the space between the valve body 2 and the valve element 3 is sealed by one of the at least one first sealing member 5 and the at least one second sealing member 6. In a second closed state, with the valve element 3 inverted, the space between the valve body 2 and the valve element 3 is sealed by the other of the at least one first sealing member 5 and the at least one second sealing member 6.

Description

Technical Field

[0001] The present invention relates to a butterfly valve.

Background Art

[0002] Generally, a butterfly valve has a cylindrical valve body, an annular valve seat or seal portion provided on the inner surface of the valve body, a valve element configured to close the flow path in close contact with the valve seat, and a valve shaft that rotatably supports the valve element with respect to the valve body. A seal member such as an O-ring is provided on the valve seat side or the valve element side, thereby preventing leakage of fluid through the seal portion, so-called internal leakage.

[0003] Normally, the seal member cannot be replaced while the butterfly valve is connected to the pipe. When replacing the seal member, it is performed with the butterfly valve removed from the pipe or with one side of the pipe removed. Therefore, it is necessary to drain the liquid (drain water) in the pipe or stop the water supply device. Also, when the fluid is at a high temperature, it is necessary to lower the temperature of the butterfly valve for the work. Furthermore, the work of removing the pipe and replacing the seal member requires longer labor and higher costs as the diameter of the butterfly valve increases. Therefore, it is desirable that the butterfly valve can be used for a long period of time without performing the work of replacing the seal member.

[0004] Patent Document 1 discloses a butterfly valve having an eccentric structure in which a seal member is provided on the valve seat and the center of the annular seal member is separated from the axis of the valve shaft. In the butterfly valve described in Patent Document 1, the position of the seal member with which the valve element abuts in the closed valve state, that is, the position of the valve seat, can be shifted from the first closed valve position to the second closed valve position by slightly changing the rotation angle of the valve element. By shifting the position of the valve seat, the seal performance deteriorated due to deterioration or wear of the seal member over time can be improved again, and the butterfly valve can be used for a long period of time without performing the work of replacing the seal member.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-141954 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in the butterfly valve described in Patent Document 1, the sealing member is a single component, and therefore the sealing member that the valve body contacts in the first closed position and the second closed position is the same. As a result, if the sealing member itself suffers significant damage, it becomes difficult to maintain the sealing performance, and the sealing member must be replaced.

[0007] The present invention aims to provide a butterfly valve that can be used for a long period of time without the need to replace the sealing member. [Means for solving the problem]

[0008] According to one aspect of the present invention, a butterfly valve is provided, comprising a cylindrical valve body, a valve element configured to close a flow path, a valve shaft that rotatably supports the valve element with respect to the valve body, and in a first closed state, at least one first sealing member provided on the upstream side of the flow path and at least one second sealing member provided on the downstream side of the flow path, wherein in the first closed state, the space between the valve body and the valve element is sealed by one of the at least one first sealing member and the at least one second sealing member, and in a second closed state with the valve element inverted, the space between the valve body and the valve element is sealed by the other of the at least one first sealing member and the at least one second sealing member.

[0009] It is preferable that the at least one first sealing member and the at least one second sealing member are provided on the valve body side.

[0010] It is preferable that the at least one first sealing member and the at least one second sealing member are provided on the valve body side.

[0011] It is preferable that the elastic modulus of the at least one first sealing member and the at least one second sealing member is lower than the elastic modulus of the valve body or the valve element.

[0012] It is preferable that the at least one first sealing member and the at least one second sealing member are separate components.

[0013] It is preferable that the separate component is fitted into a groove or recess provided in the corresponding valve body or valve element.

[0014] It is preferable that the separate component is held by a retaining member that is detachable from the corresponding valve body or valve element. [Effects of the Invention]

[0015] According to aspects of the present invention, a common effect is to provide a butterfly valve that can be used for a long period of time without the need to replace the sealing member. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a perspective view of a butterfly valve in the first closed state according to a first embodiment of the present invention. [Figure 2] Figure 2 is a perspective view of a butterfly valve in the open position. [Figure 3] Figure 3 is a longitudinal cross-sectional view of the butterfly valve in the first closed state. [Figure 4] Figure 4 is a cross-sectional view of the butterfly valve in the first closed state. [Figure 5] Figure 5 is a cross-sectional view of a butterfly valve in the open position. [Figure 6] Figure 6 is a cross-sectional view of the butterfly valve in the second closed state, with the valve body inverted. [Figure 7]FIG. 7 is a longitudinal sectional view of the butterfly valve in the first valve-closed state with the arrangement changed. [Figure 8] FIG. 8 is a longitudinal sectional view of the butterfly valve in the first valve-closed state according to the second embodiment. [Figure 9] FIG. 9 is a longitudinal sectional view of the butterfly valve in the first valve-closed state according to the third embodiment. [Figure 10] FIG. 10 is a cross-sectional view of the butterfly valve in the second valve-closed state with the valve body inverted. [Figure 11] FIG. 11 is a longitudinal sectional view of the butterfly valve in the first valve-closed state according to the fourth embodiment. [Figure 12] FIG. 12 is a longitudinal sectional view of the butterfly valve in the first valve-closed state according to the fifth embodiment. [Figure 13] FIG. 13 is a partial longitudinal sectional view showing the arrangement of another sealing member. [Figure 14] FIG. 14 is a partial longitudinal sectional view showing the arrangement of yet another sealing member.

Best Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Throughout the drawings, common reference numerals are assigned to corresponding components.

[0018] FIG. 1 is a perspective view of the butterfly valve 1 in the first valve-closed state according to the first embodiment of the present invention, FIG. 2 is a perspective view of the butterfly valve 1 in the valve-open state, FIG. 3 is a longitudinal sectional view of the butterfly valve 1 in the first valve-closed state, FIG. 4 is a cross-sectional view of the butterfly valve 1 in the first valve-closed state, and FIG. 5 is a cross-sectional view of the butterfly valve 1 in the valve-open state.

[0019] The butterfly valve 1 comprises a valve body 2 that is generally annular or cylindrical but has protrusions at two locations, upper and lower; a valve element 3 configured to close the flow path defined by the inner surface of the valve body 2; and two valve shafts 4 that rotatably support the valve element 3 from above and below relative to the valve body 2. One of the two valve shafts 4, i.e., the upper valve shaft 4, penetrates the valve body 2 and protrudes from the valve body 2. A gear mechanism (not shown) is connected to the end of the valve shaft 4 that protrudes from the valve body 2. By operating a handle connected to the gear mechanism, the valve element 3 can be rotated relative to the valve body 2. This allows the opening degree of the butterfly valve 1 to be adjusted, and also allows the valve element 3 to be freely rotated, as will be described later. Note that the rotational drive of the valve shaft may be an air-operated or electric actuator or a manual lever, in addition to the gear mechanism.

[0020] In Figure 3 and Figures 7 through 12 described later, the left side of the butterfly valve is considered the upstream side of the flow path, and the right side of the butterfly valve is considered the downstream side of the flow path. Similarly, in Figure 4 and Figures 5 and 6 described later, the upper side of the butterfly valve is considered the upstream side of the flow path, and the lower side of the butterfly valve is considered the downstream side of the flow path.

[0021] In the width direction of the annular outer surface of the valve body 3, a first seal member 5 is provided as an annular seal member on the upstream side, and a second seal member 6 is provided as an annular seal member on the downstream side. An annular valve seat or seal portion 7 is provided on the upstream inner surface of the valve body 2, opposite the first seal member 5. The seal portion 7 is formed by a slanted inner surface that gradually decreases in diameter in the direction away from the valve body 3 or valve stem 4. In the closed valve state as shown in Figures 3 and 4, the first seal member 5 is in close contact with the seal portion 7 around its entire circumference, thereby sealing the space between the valve body 2 and the valve body 3. At this time, the second seal member 6 is not in contact with the downstream inner surface of the valve body 2. The butterfly valve 1 is an eccentric butterfly valve in which the center of the annular seal member and the rotation axis C of the valve stem 4 are spaced apart.

[0022] The first sealing member 5 and the second sealing member 6 are the same member, but they may be different members. The elastic modulus of the first sealing member 5 and the second sealing member 6 is lower than the elastic modulus of the valve body 2 or the valve element 3. Generally, the tensile elastic modulus is used. Each of the first sealing member 5 and the second sealing member 6 is held in place by fitting into an annular recess or groove 8 provided on the outer surface of the valve element 3 while undergoing elastic deformation. The groove 8 has, for example, a substantially rectangular cross-section, but is not limited to this. The first sealing member 5 and the second sealing member 6 are, for example, rubber O-rings, but are not limited to these as long as they can seal, and include resin or rubber O-rings or annular packing members, metal ring members, coil springs and spring washers, etc.

[0023] The material of the first sealing member 5 and the second sealing member 6 is preferably one with lower physical properties than the material of the valve body 2 or valve element 3. Physical properties include not only the modulus of elasticity but also wear resistance and hardness. Resins and rubbers are particularly preferred as the material of the first sealing member 5 and the second sealing member 6. Examples include rubber elastic materials such as butyl rubber (BR), chloroprene rubber (CR), ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPM), isoprene rubber (IR), chlorosulfonated rubber (CSM), nitrile rubber (NBR), styrene butadiene rubber (SBR), chlorinated polyethylene (CM), fluororubber (FRM), hydrogenated acrylonitrile butadiene rubber (HNBR), urethane rubber (U), silicone rubber (VMQ, FVMQ), and acrylic rubber (ACM); fluororesins such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkanes (PFA); and fluororesin-coated rubber elastic materials such as PTFE and PFA.

[0024] Furthermore, the material of the valve body 2 or valve element 3 may be resin or metal, etc., as long as its physical properties are superior to those of the first sealing member 5 and the second sealing member 6, but it is particularly preferable that it be formed from a synthetic resin material. Examples include synthetic resin materials such as polyvinyl chloride (PVC), polypropylene (PP), polyvinylidene fluoride (PVDF), polyethylene (PE), polyphenylene sulfide (PPS), polydicyclopentadiene (PDCPD), polytetrafluoroethylene (PTFE), acrylonitrile butadiene styrene resin (ABS resin), chlorinated polyvinyl chloride (PVC-C), perfluoroalkoxy alkanes (PFA), and fiber-reinforced plastics (FRP), as well as synthetic resin materials reinforced with glass fibers or the like. Also, the valve body 2 or valve element 3 may be made of the same material or different materials.

[0025] The valve body 3, including the first sealing member 5 and the second sealing member 6, is configured to be rotationally symmetrical with respect to the rotation axis C of the valve stem 4. Therefore, even if the valve body 3, which is in the closed state, is rotated 180 degrees, i.e., inverted, the butterfly valve 1 can still be closed. This will be explained with reference to Figures 4 to 6. Figure 6 is a cross-sectional view of the butterfly valve 1 in the second closed state, with the valve body 3 inverted.

[0026] As described above, in the butterfly valve 1 shown in Figure 4, the valve body 2 and the valve element 3 are sealed by the first sealing member 5 making tight contact with the sealing portion 7 around its entire circumference. This closed state is called the first closed state. From the first closed state, for example, rotating the valve element 3 clockwise in Figure 4 results in the open state shown in Figure 5. Furthermore, if the valve element 3 is rotated further, that is, if the valve element 3 is reversed from the first closed state shown in Figure 4, the butterfly valve 1 will once again be in the closed state, as shown in Figure 6. In the butterfly valve 1 shown in Figure 6, the valve body 2 and the valve element 3 are sealed by the second sealing member 6 making tight contact with the sealing portion 7 around its entire circumference. This closed state is called the second closed state.

[0027] The first closed state and the second closed state can be easily switched by simply reversing the valve body 3. For example, if the butterfly valve 1 is used for a while in the first closed state, sealed by the first sealing member 5, and as a result the sealing performance deteriorates due to deterioration, wear, or damage to the first sealing member 5 over time, then by reversing the valve body 3 to the second closed state, the space between the valve body 2 and the valve body 3 can be sealed using the unused second sealing member 6, thereby improving the sealing performance again. In addition, although the butterfly valve of the present invention is configured to be able to rotate 180°, it is desirable to configure it so that it can be switched to opening and closing with a 90° rotation when using the first closed state and when using the second closed state, respectively.

[0028] As a result, the overall lifespan of the sealing components can be approximately doubled, making it possible to use the butterfly valve for a long period of time without replacing the sealing components. Furthermore, since the first sealing component 5 and the second sealing component 6 are separate components, even if the first sealing component 5 itself suffers significant damage, the sealing performance can be maintained by using the second sealing component 6. In addition, the frequency of sealing component replacement work is reduced, which reduces the labor and costs associated with replacing sealing components, and also reduces the risk of chemical fluid splashing that may occur during replacement work.

[0029] Figure 7 is a longitudinal cross-sectional view of the butterfly valve 1 in the first closed state with a modified arrangement. Specifically, the arrangement of the butterfly valve 1 shown in Figure 7 is modified from the arrangement of the butterfly valve 1 shown in Figure 3 by swapping the upstream and downstream sides. In Figure 7, the left side of the butterfly valve 1 is the upstream side of the flow path, and the right side of the butterfly valve is the downstream side of the flow path. In the width direction of the annular outer surface of the valve body 3, a first seal member 5 is provided on the downstream side, and a second seal member 6 is provided on the upstream side. An annular seal portion 7 is provided on the inner surface of the downstream side of the valve body 2, opposite the first seal member 5.

[0030] In the butterfly valve 1 shown in Figure 7, the first closed state is achieved when the first sealing member 5 is in close contact with the sealing portion 7 around its entire circumference on the downstream side of the flow path, thereby sealing the space between the valve body 2 and the valve element 3. At this time, the second sealing member 6 is not in contact with the downstream inner surface of the valve body 2 on the upstream side of the flow path. By reversing the valve element 3 from this state, it is possible to switch between the first closed state and the second closed state. In short, as shown in Figures 3 and 7, the sealing portion 7 may be provided on the upstream or downstream side depending on the application and purpose of use.

[0031] Hereinafter, with reference to Figures 8 to 10, a butterfly valve according to another embodiment of the present invention that achieves effects similar to those described above will be described. In the description of each embodiment, the same reference numerals are used for the same components, and their descriptions will be omitted.

[0032] Figure 8 is a longitudinal cross-sectional view of the butterfly valve 10 in the first closed state according to the second embodiment. Compared to the butterfly valve 1 according to the first embodiment, the butterfly valve 10 differs in the shape and structure of the valve body, specifically in the holding structure of the first sealing member 5 and the second sealing member 6.

[0033] As shown in Figure 8, stepped recesses 18 are provided around the entire circumference of the upstream and downstream periphery of the valve body 13. The first seal member 5 and the second seal member 6 are positioned along the recesses 18 of the valve body 13, and then held in place by a retaining member 19 that is attached to the valve body 13 so as to sandwich it between them. The retaining member 19 is an annular, plate-shaped member and is detachably fastened to the valve body 13 by screws or bolts. In other words, the recesses 18 are formed such that the first seal member 5 and the second seal member 6 are sandwiched by the retaining member 19, and the surface of the retaining member 19 is flush with the surface of the valve body 13.

[0034] Since the first sealing member 5 and the second sealing member 6 are held in place by the retaining member 19 against the valve body 13, the first sealing member 5 and the second sealing member 6 can be easily attached to and detached from the valve body 13 compared to the case where they are fitted into the groove 8 while being elastically deformed. In other words, the replacement of the first sealing member 5 and the second sealing member 6 can be easily performed. Furthermore, by configuring the retaining member 19 to lock into the first sealing member 5 and the second sealing member 6, unintended detachment of the first sealing member 5 and the second sealing member 6 can be prevented.

[0035] Figure 9 is a longitudinal cross-sectional view of the butterfly valve 20 in the first closed state according to the third embodiment. The butterfly valve 20 differs from the butterfly valve 1 according to the first embodiment in that the first sealing member and the second sealing member are provided on the valve body side rather than on the valve body side.

[0036] As shown in Figure 9, annular and stepped recesses 28 are provided on the inner surfaces of the valve body 22 on the upstream and downstream sides near the valve body 23 in the first closed state. The first sealing member 15 and the second sealing member 16 are positioned along the recesses 28 of the valve body 22 and then held in place by the retaining member 29, which is attached to the valve body 22 so as to sandwich them between the retaining member 29. The retaining member 29 is an annular member and is detachably fastened to the valve body 22 by screws or bolts. In other words, the recesses 28 are formed such that the first sealing member 15 and the second sealing member 16 are sandwiched by the retaining member 29, and the surface of the retaining member 29 is flush with the surface of the valve body 23. The first sealing member 15 and the second sealing member 16 are, for example, metal ring members. The elastic modulus of the first sealing member 15 and the second sealing member 16 is lower than the elastic modulus of the valve body 22 or the valve body 23.

[0037] The inner surface of the valve body 22, including the first sealing member 15, the second sealing member 16, and the retaining member 29, is configured to be rotationally symmetrical with respect to the rotation axis C of the valve stem 4. On the other hand, the valve body 23 is not configured to be rotationally symmetrical. That is, in the first closed valve state shown in Figure 9, the outer diameter of the upstream valve body 23 is formed to be larger than the outer diameter of the downstream valve body 23, forming a sealing portion 27. The valve body 22 and the valve body 23 are sealed by the first sealing member 15 making tight contact with the sealing portion 27 around its entire circumference. The butterfly valve 20 is an eccentric butterfly valve in which the center of the annular sealing member and the rotation axis C of the valve stem 4 are spaced apart.

[0038] Figure 10 is a cross-sectional view of the butterfly valve 20 in the second closed state, with the valve body 23 inverted. Like the butterfly valve 1 and butterfly valve 10 described above, the butterfly valve 20 can be switched to the second closed state by inverting the valve body 23. In the second closed state, the unused second sealing member 16 is in close contact with the sealing portion 27 around its entire circumference, thereby sealing the space between the valve body 22 and the valve body 23.

[0039] In the butterfly valve 20, a sealing member is located on the valve body 22 side. However, since the sealing member used can be switched from the first sealing member 15 to the second sealing member 16, the butterfly valve 20 can be used for a long period of time without having to replace the sealing member.

[0040] Furthermore, since the first sealing member 15 and the second sealing member 16 are held by a detachable retaining member 29, the replacement of the first sealing member 15 and the second sealing member 16 can be easily performed. In addition, by configuring the retaining member 29 to lock into the first sealing member 15 and the second sealing member 16, unintended detachment of the first sealing member 15 and the second sealing member 16 can be prevented. Alternatively, the first sealing member 15 and the second sealing member 16 may be directly attached to the valve body 22 by fitting or adhesive without using the retaining member 29.

[0041] In the butterfly valve 10 according to the second embodiment, a seal portion 7 is provided on the inner surface on the upstream side of the valve body 2. However, as explained with reference to Figure 7 regarding the butterfly valve 1 according to the first embodiment, the seal portion may also be provided on the inner surface on the downstream side. In short, in Figure 3, the butterfly valve may be positioned with the right side of the flow path being the upstream side and the left side of the flow path being the downstream side. In the butterfly valve 20 according to the third embodiment, the seal portion 27 is positioned on the upstream side in the first closed state and on the downstream side in the second closed state. However, the seal portion 27 may be positioned on the downstream side in the first closed state and on the downstream side in the second closed state. In short, in Figures 9 and 10, the butterfly valve may be positioned with the right side of the flow path being the upstream side and the left side of the flow path being the downstream side. Furthermore, in the embodiments described above, the butterfly valve has, in the first closed state, one first seal member provided on the upstream side of the flow path and one second seal member provided on the downstream side of the flow path, but it may have two or more first seal members and / or two or more second seal members.

[0042] Based on the above, the butterfly valve may have at least one first sealing member provided on the upstream side of the flow path and at least one second sealing member provided on the downstream side of the flow path in the first closed state. Alternatively, the butterfly valve may be configured such that in the first closed state, the space between the valve body and the valve element is sealed by at least one first sealing member and at least one second sealing member, and in the second closed state, with the valve element inverted, the space between the valve body and the valve element is sealed by the other of the at least one first sealing member and at least one second sealing member.

[0043] The arrangement of the first and second sealing members only needs to be rotationally symmetrical with respect to the sealing portion; the member holding the first and second sealing members, i.e., the inner surface of the valve body or the valve body as a whole, does not need to be rotationally symmetrical. The embodiments described above were all butterfly valves with a primary eccentric structure, but butterfly valves with a secondary eccentric structure or other eccentric structures may also be used.

[0044] In the butterfly valve according to the above-described embodiment, the shape of the valve body portion and the valve stem, which do not directly contribute to the sealing performance using the sealing member, can be arbitrarily configured as shown in Figures 11 to 14.

[0045] Figure 11 is a longitudinal cross-sectional view of the butterfly valve 30 in the first closed state according to the fourth embodiment. As shown in Figure 11, a recess 33a may be provided in the central part of the valve body 33. Figure 12 is a longitudinal cross-sectional view of the butterfly valve 40 in the first closed state according to the fifth embodiment. As shown in Figure 12, the valve stem 44 may be a single member, and the valve stem 44 may be rotatably supported while passing through the valve body 43.

[0046] Figure 13 is a partial longitudinal cross-sectional view showing the arrangement of another sealing member 55. In the butterfly valve 1 described above, the first sealing member 5 and the second sealing member 6 are fitted into a groove 8 having a substantially rectangular cross-section. The groove 58 shown in Figure 13 has a substantially trapezoidal cross-section, with the width inside the groove 58 being wider than the width of the inlet portion. Therefore, by fitting the sealing member 55 into the groove 58 while elastically deforming it, the sealing member 55 and the groove 58 can be locked more firmly, preventing the sealing member 55 from unintentionally coming off.

[0047] Figure 14 is a partial longitudinal cross-sectional view showing the arrangement of yet another sealing member 65. The groove 68 shown in Figure 14 has an inverted T-shaped cross-section, where the width inside the groove 58 is wider than the width at the entrance. The sealing member 65 also has a similar cross-section. Therefore, by fitting the sealing member 65 into the groove 68 while elastically deforming it, the sealing member 65 and the groove 68 can be more firmly locked together, preventing the sealing member 65 from unintentionally coming off.

[0048] The sealing member may be an annular member having a non-circular cross-section, as described with reference to Figure 14. The sealing member may be formed integrally with the valve body or valve element. [Explanation of symbols]

[0049] 1 Butterfly valve 2 Valve body 3 Valve body 4 Valve stem 5. First sealing member 6. Second sealing member 7. Seal part 8 grooves

Claims

1. A cylindrical valve body, A valve body configured to be able to close the flow path, A valve shaft that rotatably supports the valve body with respect to the valve body, In the first closed valve state, the device comprises at least one first sealing member provided on the upstream side of the flow path and at least one second sealing member provided on the downstream side of the flow path. In the first closed valve state, the space between the valve body and the valve element is sealed by at least one of the first sealing members and at least one of the second sealing members. A butterfly valve configured such that, in a second closed state with the valve body inverted, the space between the valve body and the valve element is sealed by the other of the at least one first sealing member and the at least one second sealing member.

2. The butterfly valve according to claim 1, wherein the at least one first sealing member and the at least one second sealing member are provided on the valve body side.

3. The butterfly valve according to claim 1, wherein the at least one first sealing member and the at least one second sealing member are provided on the valve body side.

4. The butterfly valve according to claim 1, wherein the elastic modulus of the at least one first sealing member and the at least one second sealing member is lower than the elastic modulus of the valve body or the valve element.

5. The butterfly valve according to any one of claims 1 to 4, wherein the at least one first sealing member and the at least one second sealing member are separate members.

6. The butterfly valve according to claim 5, wherein the separate member is fitted into a groove or recess provided in the corresponding valve body or valve element.

7. The butterfly valve according to claim 5, wherein the separate component is held by a retaining member that is detachable from the corresponding valve body or valve element.

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